Cs or Trd, H, FQs, Eto or Pto, Ipm/Cln or Mpm
All the above-mentioned drugs may cause seizures. However, rule out or treat other possible causes (e.g. epilepsy, meningitis, encephalitis, alcohol withdrawal, hypoglycaemia, stroke, cancer, or toxoplasmosis in HIV-infected patients).
In the event of seizures, measure blood glucose level and blood electrolytes. Measure also serum creatinine. With impaired renal function, TB drugs can reach toxic levels, causing seizures. Dosage adjustment may be necessary (Appendix 12).
A history of seizures is not an absolute contra-indication to the use of the above-mentioned drugs. However, do not use Cs or Trd if there is an alternative. In patients with epilepsy, seizures should be controlled with antiseizure medications (ASM) before starting TB treatment.
The use of TB drugs (especially H and R) in patients on ASM may lead to decreased plasma concentrations of ASM and seizures.
In patients without history of seizures, a first episode of seizures on TB treatment is likely due to the TB drugs. However, none of the above drugs leave permanent damage.
If a patient has a seizure for the first time:
- Stop suspected TB drugs for a short period.
- Start ASM treatment, especially in the event of repeated seizures after stopping suspected drugs. Do not use carbamazepine or phenytoin in patients receiving Bdq or Dlm (strong CYP450 inducers).
- Reintroduce TB drugs that are essential to TB treatment. Usually, they can be resumed at a lower dose, but the effective dose should be reached as soon as possible.
Antiseizure treatment may be necessary until the end of the TB treatment.